The fires of San Telmo are greenish or bluish glitters that appear suspended on pointed objects located on land. The luminosity is caused by the air molecules excited by the electric field that is generated, which creates a continuous flow of small sparks, usually invisible.
Benjamin Franklin He was the first to determine in 1749 that the nature of the fires of San Telmo is electric. Although it is called "fire", it is actually a low density and relatively low temperature plasma caused by a huge difference in atmospheric electrical potential.
This phenomenon takes its name from Erasmus of Formia (San Elmo), patron saint of sailors, as there are numerous sailors who, throughout history, claim to have witnessed the appearance of tongues of incandescent fire that danced on the masts and ends of the arboladura of ships during certain storms; accompanied, as if that were not enough, alterations of the compass, as if they were being victims of a "meeting in the third phase".
These fires of San Telmo, specifically, served to sailors to predict the fall of an impending ray on the ship, as it usually precedes them.
So this overwhelming light phenomenon was a symbol of bad fury among sailors. In Moby dick, from Herman MelvilleFor example, you can read a clear allusion to them.
During storms especially charged with electricity, the phenomenon can also be observed on the tips of the horns of cattle, on the leaves of trees, on the grass and on sharp objects that dance in the middle of a tornado, as if the fire of St. Telmo will give everything we see a spooky air. For example, in the comic Tintin in Tibet the appearance of a fire of San Telmo in the ax of the Captain Haddock.
They also appear on airplanes and airships, and in fact there is a theory that indicates that the famous fire of airship Hindenburg In 1937 it was the work of a San Telmo fire, which ignited the hydrogen that raised the device. Something that fortunately could no longer happen with what is considered the largest aircraft in the world. Because helium balloons can't burn.
In ancient Greece, the appearance of a single fire of San Telmo was called Helena and when they were two they were called Beaver Y Pollux. The Welsh sailors referred to this phenomenon as anwyll Y ysbryd (candles of the spirits) or candles of the holy ghost or Saint David. For the Russians it was the lights of St. Nicholas or St. Peter.